[kvm-unit-tests RFC v3 10/13] s390x: Add linemode buffer to fix newline on every print

[Janosch Frank <frankja@xxxxxxxxxxxxx>]

Linemode seems to add a newline for each sent message which makes
reading rather hard. Hence we add a small buffer that and only print
if it's full or a newline is encountered.

Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
---
 lib/s390x/sclp-console.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/lib/s390x/sclp-console.c b/lib/s390x/sclp-console.c
index f0ce6a0..34edae5 100644
--- a/lib/s390x/sclp-console.c
+++ b/lib/s390x/sclp-console.c
@@ -88,6 +88,9 @@ static uint8_t _ascebc[256] = {
 };
 
 static bool initialized;
+static char lm_buff[120];
+static unsigned char lm_buff_off;
+
 
 static void sclp_print_ascii(const char *str)
 {
@@ -116,6 +119,18 @@ static void sclp_print_lm(const char *str)
 	struct mdb *mdb;
 	struct mto *mto;
 	struct go *go;
+	char *nl;
+
+	len = strlen(str);
+	len = len < (sizeof(lm_buff) - lm_buff_off) ? len : (sizeof(lm_buff) - lm_buff_off);
+	nl = strchr(str, '\n');
+	if ((lm_buff_off < sizeof(lm_buff) - 1)) {
+		memcpy(&lm_buff[lm_buff_off], str, len);
+		lm_buff_off += len;
+	}
+	/* Buffer not full and no newline */
+	if (lm_buff_off != sizeof(lm_buff) - 1 && !nl)
+		return;
 
 	sclp_wait_busy();
 	sclp_busy = true;
@@ -123,11 +138,11 @@ static void sclp_print_lm(const char *str)
 	end = (unsigned char *) sccb + 4096 - 1;
 	memset(sccb, 0, sizeof(*sccb));
 	ptr = (unsigned char *) &sccb->msg.mdb.mto;
-	len = strlen(str);
+	len = strlen(lm_buff);
 	offset = 0;
 	do {
 		for (count = sizeof(*mto); offset < len; count++) {
-			ch = str[offset++];
+			ch = lm_buff[offset++];
 			if ((ch == 0x0a) || (ptr + count > end))
 				break;
 			ptr[count] = _ascebc[ch];
@@ -154,6 +169,8 @@ static void sclp_print_lm(const char *str)
 	go->type = 1;
 	sclp_service_call(SCLP_CMD_WRITE_EVENT_DATA, sccb);
 	sclp_wait_busy();
+	memset(lm_buff, 0 , sizeof(lm_buff));
+	lm_buff_off = 0;
 }
 
 /*
-- 
2.14.3